a) Field of the Invention
This invention relates to an operating microscope, specifically to that incorporating an endoscopic image into an operating-microscopic image to allow simultaneous observation.
b) Description of the Related Art
For surgical treatment in cerebral neurosurgery, otorhinolaryngology, ophthalmology or other clinical specialty, operating microscopes have played such an important role as to improve efficiency of surgical operations by providing observers with enlarged images of parts subjected to the operations. Furthermore, in recent years, endoscopic observation also is applied to the operations that used to be performed only under the operating-microscopic observation, so that tissues other than the minimum necessary portions for the operation remain intact; it is preferred that the operating-microscopic image and the endoscopic image can be observed simultaneously.
A microscope apparatus disclosed by Japanese Patent Application Laid-Open Number Sho 62-166310, for example, is known to be directed to the combination of the operating microscope and the endoscope. In this apparatus, an endoscope with a solid-state image pickup device for stereoscopic observation is provided to be movable with respect to a stereoscopic microscope so as to allow observation inside a narrow cavity, which were impossible otherwise. Moreover, the apparatus includes an image reproducing means for displaying the image derived from the solid-state image pickup device and an image projecting means for introducing the image displayed on the image reproducing means into an eyepiece optical system so that the eyepiece optical system is commonly used for simultaneous observation of the operating-microscopic image and the endoscopic image.
However, the art of the Japanese Patent Application Laid-Open Number Sho 62-166310 fails to consider the problem caused by the shift of the image surfaces which are provided for observation via eyepiece, which shift accompanies adjustment of interpupillary distance, and thus cannot be reduced into realization for a practical operating microscope.
The adjustment of interpupillary distance is performed by shifting the left and right sections of the operating microscope, in each of which an image surface is provided for observation via eyepiece, so that the distance between the left and right eyepoints of the operating microscope corresponds to the distance between the left and right pupils of an observer. Every operating microscope is provided with a mechanism to perform this adjustment. If the interpupillary distance is to be adjusted in practice using only the art known from the above-mentioned Sho 62-166310, it is necessary to shift the image reproducing means through the image projecting means integral with the shift of the image surfaces provided for observation via eyepiece so that the positions on which the images from the image reproducing means are projected follow movement of the eyepiece optical system resulting from the adjustment of interpupillary distance. This configuration requires a space for movement of optical system or elements inside a housing of the operating microscope, to render the housing voluminous. As a result, according to the art of the above-mentioned Sho 62-166310, it is impossible to make an operating microscope compact in its entirety, while the operating microscope is fundamentally required to be made compact for efficiency of the surgical work.